Fuel cell module

Abstract

A fuel cell module includes in a casing: a fuel cell stack that is formed by stacking a plurality of unit cell; an oxidant gas distributing member that is disposed at a side surface, that extends in a stack direction of the unit cells, of the fuel cell stack that extends in a direction from one end to another end of each of the unit cells, and that supplies the oxidant gas to the another end of each unit cell after supplying the oxidant gas through the oxidant gas distributing member from the one end to the another end; a reformer disposed at the one end; and a combustion portion that is disposed between the one end and the reformer. The oxidant gas distributing member has a higher thermal conductivity at the one end side of the unit cells than at the another end side of the unit cells.

The invention claimed is: 
     
       1. A fuel cell module comprising:
 a fuel cell stack that is formed by stacking a plurality of unit cells that generate electricity using an oxidant gas and a fuel gas; 
 an oxidant gas distributing member that is disposed on a side of a side surface which extends along a stack direction of the unit cells in the fuel cell stack, and that distributes the oxidant gas for use for electricity generation of the unit cells from one end side toward the other end side of each of the unit cells and then supplies the oxidant gas to the other end side of each of the unit cells; 
 a reformer that is disposed on the one end side of each of the unit cells; and 
 a combustion portion that is disposed between the one end side of each of the unit cells and the reformer, and that burns a fuel off-gas that is left unused in the electricity generation of the unit cells, using an oxidant off-gas that is left unused in the electricity generation of the unit cells, 
 the fuel cell stack, the oxidant gas distributing member, the reformer, and the combustion portion being arranged in a casing, 
 wherein the oxidant gas distributing member has at least one of a structure in which the oxidant gas distributing member has a fin on an external surface or an internal surface of a side wall at a portion corresponding to the one end side of each of the unit cells and does not have the fin on either the external surface or the internal surface of the side wall at a portion corresponding to the other end side of each of the unit cells, a structure in which the oxidant gas distributing member has a partition member that partitions a channel into a plurality of paths at the portion corresponding to the one end side of each of the unit cells and does not have the partition member in the path at the portion corresponding to the other end side of each of the unit cells, and a structure in which the oxidant gas distributing member has a dimple on the external surface or the internal surface of the side wall at the portion corresponding to the one end side of each of the unit cells and does not have the dimple on either the external surface or the internal surface of the side wall at the portion corresponding to the other end side of each of the unit cells, thereby having a higher thermal conductivity at the portion corresponding to the one end side of each of the unit cells than at the portion corresponding to the other end side of each of the unit cells. 
 
     
     
       2. A fuel cell module comprising:
 a fuel cell stack that is formed by stacking a plurality of unit cells that generate electricity using an oxidant gas and a fuel gas; 
 a reformer that is disposed on one end side of each of the unit cells; 
 a combustion portion that is disposed between the one end side of each of the unit cells and the reformer, and that burns a fuel off-gas that is left unused in the electricity generation of the unit cells, using an oxidant off-gas that is left unused in the electricity generation of the unit cells; and 
 an oxidant gas distributing member that is disposed on a side of a side surface which extends along a stack direction of the unit cells in the fuel cell stack, that distributes the oxidant gas for use for electricity generation of the unit cells through the reformer, the combustion portion, and from the one end side to the other end side of each of the unit cells in this order and then supplies the oxidant gas to the other end side of the unit cells, 
 the fuel cell stack, the reformer, the combustion portion and the oxidant gas distributing member being arranged in a casing, wherein 
 in the oxidant gas distributing member, a portion corresponding to the one end side of each of the unit cells protrudes toward the side surface of the fuel cell stack, with respect to a portion corresponding to the other end side of each of the unit cells. 
 
     
     
       3. A fuel cell module comprising:
 a fuel cell stack that is formed by stacking a plurality of unit cells that generate electricity using an oxidant gas and a fuel gas; 
 an oxidant gas distributing member that is disposed on a side of a side surface which extends along a stack direction of the unit cells in the fuel cell stack, and that distributes the oxidant gas for use for electricity generation of the unit cells from one end side toward the other end side of each of the unit cells and then supplies the oxidant gas to the other end side of each of the unit cells; 
 a reformer that is disposed on the one end side of each of the unit cells; 
 a combustion portion that is disposed between the one end side of each of the unit cells and the reformer, and that burns a fuel off-gas that is left unused in the electricity generation of the unit cells, using an oxidant off-gas that is left unused in the electricity generation of the unit cells; and 
 internal thermal insulation members that are disposed on sides of respective surfaces which extend along a stack direction of the unit cells in the fuel cell stack, 
 the fuel cell stack, the oxidant gas distributing member, the reformer, the combustion portion, and the internal thermal insulation members being arranged in a casing, 
 wherein among the internal thermal insulation members that are disposed on the sides of the respective surfaces, the internal thermal insulation member that is disposed on the oxidant gas distributing member side is divided into a plurality of internal thermal insulation members from the other end side to the one end side of each of the unit cells, and 
 among the plurality of the internal thermal insulation members obtained through division the internal thermal insulation member, which is located at a position corresponding to the one end side of each of the unit cells has a higher thermal conductivity than the internal thermal insulation member, which is located at a position corresponding to the other end side of each of the unit cells. 
 
     
     
       4. The fuel cell module according to  claim 3 , wherein the internal thermal insulation member that is disposed on the oxidant gas distributing member side is divided into a plurality of internal thermal insulation members such that thermal conductivity increases stepwise from the other end side to the one end side of each of the unit cells.